The overall objective of this study is to investigate the mechanisms whereby immune complexes may initiate and sustain chronic inflammatory reactions. This investigation is based on the previous observation made in this laboratory that in rabbits previously immunized to an antigen, the local injected antigen is retained for long periods of time in the form of immune complexes not in synovium but in collagenous joint tissues such as articular cartilage, menisci, and intra-articular ligaments. The goals of the research effort consist of (1) the mechanisms whereby the immune complex is trapped in collagenous tissues and may sustain a prolonged chronic inflammatory process; (2) the mode of association of immune complexes to collagenous tissues and its component; (3) the possible binding of immunoglobulin to one of the components of collagenous tissues as the basis for the persistence of the immune complexes retained in these tissues and (4) the presence and nature of immunoglobulin associated with human joint collagenous tissue obtained from patients with rheumatoid arthritis, osteoarthritis or traumatic arthritis.